Quick Answer
A 24 foot round swimming pool holds approximately 13,000 gallons of water. The exact amount depends on the depth of the pool. This quick answer provides a rough estimate for a typical 4-5 foot deep residential pool.
Calculating the Volume of a Round Pool
To calculate the volume of water in a round swimming pool, you need to know:
1. The diameter of the pool
2. The depth of the pool
The volume of a cylinder can be calculated using the following formula:
Volume = π x r2 x h
Where:
π (pi) = 3.14159
r = radius of the pool (diameter ÷ 2)
h = depth of the pool
So for a 24 foot diameter pool that is 4 feet deep:
1. Diameter = 24 feet
2. Radius = Diameter ÷ 2 = 24 ÷ 2 = 12 feet
3. Depth = 4 feet
Plugging these numbers into the formula:
Volume = 3.14159 x (12 ft)2 x 4 ft
= 3.14159 x 144 ft2 x 4 ft
= 1,769 ft3
To convert cubic feet to gallons, multiply by 7.481 gallons per cubic foot:
1,769 ft3 x 7.481 gallons/ft3 = 13,223 gallons
So a 24 foot diameter by 4 foot deep round pool holds approximately 13,000 gallons of water.
Pool Volume Calculator
You can use the following calculator to determine the volume of water in a round swimming pool based on the diameter and depth:
| Pool Diameter (feet): | |
| Pool Depth (feet): | |
| Volume (gallons): |
To use: enter the diameter and depth of your round pool, then click “Calculate” to determine the approximate volume in gallons.
Factors that Affect Water Volume
The actual amount of water needed to fill a swimming pool to the desired depth depends on several factors:
– Shape of the pool – The volume calculations here are based on a perfect circle. Kidney-shaped or oval pools require a more complex formula.
– Depth variance – Many pools have deeper and shallower sections. The deeper sections require more water.
– Curved bottom – Pool floors are rarely flat. A curved or sloped bottom means more water is needed for the deeper sections.
– Steps, benches, swimouts – Built-in seating and entry areas displace water. The volume of the seating areas needs to be subtracted from the total.
– Hollow fill areas – Some pool designs have hollow cavities behind water features and walls to create the illusion of more water. These hollow areas should not be included in volume calculations.
– Overflow system – The gutters and balance tank add volume that must be accounted for when filling the pool.
– Plumbing lines – The pipes and filtration system contain water that is not directly in the pool bowl. This volume may need to be added.
– Splash out – When people use the pool, water is displaced and splashes out. The volume lost should be included when topping off the pool.
– Surface disturbance – Wind and waves result in a disturbed water surface, which can decrease overall volume compared to a flat surface.
Due to these factors, the total volume of water in a pool is usually 5-10% greater than the calculations for a perfect cylinder suggest. It’s best to multiply the volume by 1.05 or 1.1 to allow for these additional volumes.
Dimensions of Common Pool Sizes
Here are some typical dimensions and volumes for common round pool sizes:
| Pool Diameter | Average Depth | Approx. Volume (gal) |
|---|---|---|
| 16 ft | 4 ft | 6,000 |
| 18 ft | 4 ft | 8,000 |
| 20 ft | 4 ft | 10,000 |
| 24 ft | 4 ft | 13,000 |
| 28 ft | 4 ft | 16,000 |
| 32 ft | 4 ft | 20,000 |
| 16 ft | 6 ft | 9,000 |
| 18 ft | 6 ft | 12,000 |
| 20 ft | 6 ft | 15,000 |
| 24 ft | 6 ft | 19,500 |
| 28 ft | 6 ft | 24,000 |
| 32 ft | 6 ft | 30,000 |
These volumes are just estimates – the actual amount of water needed may vary by 10-15% depending on pool shape and the other factors discussed above. Always consult your pool installer for the exact volume.
How Much Does Pool Water Weigh?
Water is heavy – about 8.34 pounds per gallon. So a 24′ round pool holding 13,000 gallons contains over 108,000 pounds or 54 tons of water!
This tremendous weight is why proper structural design for an in-ground pool is so important. The walls must withstand the outward pressure of the water continually pushing against them.
Above-ground pool frames need to handle the massive weight also. The entire weight of the water rests on the ledge at the bottom of the pool wall, requiring very strong materials.
Some pounds-per-gallon equivalents:
– 6,000 gallon pool = 50,040 lbs
– 10,000 gallon pool = 83,400 lbs
– 15,000 gallon pool = 125,100 lbs
– 20,000 gallon pool = 166,800 lbs
– 25,000 gallon pool = 208,500 lbs
As you can see, the water weight adds up quickly. Make sure any pool you purchase is designed by qualified engineers to handle the loads safely.
How Much Does Pool Water Cost?
The cost to fill a pool depends on your local water rates. Many utilities charge tiered rates based on usage. Typical water costs range from $2 to $5 per 1,000 gallons.
At $2/1,000 gallons, filling a 24′ round 4′ deep pool would cost around $26. At $5/1,000 gallons, the cost would be $65.
However, these are just the initial fill costs. Evaporation, splash out, and draining will continually lower the water level over time. Expect to add 1/4 to 1/2 inch of water to your pool per week during the swimming season, equating to 500-1,000 gallons for a typical 24′ pool.
This regular top-off water can really add up for commercial or public pools. One study found topping off a 20,000 gallon commercial pool costs around $2,500 annually.
Using a pool cover whenever the pool is not in use can significantly reduce evaporative losses and save on water expenses. Some other tips for saving water include:
– Maintaining proper water chemistry to minimize draining
– Checking regularly for leaks
– Using landscaping or wind barriers to reduce splash out
– Operating filtration systems for minimum time required
– Lowering the pool water level in the off-season
With utilities, chemical, heating, and maintenance costs, owning a home swimming pool results in a significant increase in water expenses compared to households without a pool.
Tips for Filling a Large Pool
Filling a swimming pool, especially larger pools of 15,000+ gallons, requires some planning and preparation:
– Confirm your home’s plumbing can handle the flow rate. Pumps may be required for pools over 15,000 gallons.
– Have a trucked-in water delivery if your house supply is insufficient.
– Inspect the empty pool thoroughly before filling. Look for cracks or leaks.
– Cover drains and check hydrostatic valves to prevent backflow into municipal lines.
– Remove all debris from the pool. Hose down surfaces.
– Connect garden hoses to hose bibs using gasketed couplings to prevent leaks. Consider large 2.5″ diameter hoses.
– Fill slowly, ideally over 24-48 hours, to allow monitoring and prevent structural damage.
– Visually inspect all sides for leaks as the water level rises. Stop filling immediately if a leak is observed.
– Do not allow children to access the pool during the unsafe, empty or partially filled state.
– Carefully follow all safety, chemical handling, and equipment operating procedures.
Filling a pool too quickly can damage the pool structure, equipment, decking and surrounding surfaces due to the rapid increase in hydrostatic pressure. Take things slow and follow the manufacturer’s fill rate recommendations.
Draining and Refilling a Pool
Pools should be periodically drained and refilled for several reasons:
– To maintain proper chemical balance and sanitization. Pool water collects organic contaminants, minerals, and chemicals over time. Draining allows starting fresh.
– To conduct repairs or resurfacing. Fixing cracks, leaks, or recoating surfaces often requires emptying the pool.
– For cleaning. Draining fully allows scrubbing all surfaces thoroughly. Some debris and stains are hard to remove with a full pool.
– After severe storms or floods. Contaminants can enter the water, requiring draining.
– For winterization in cold climates. Lowering the water level reduces hydrostatic pressure on the pool walls and prevents ice damage.
The frequency for draining depends on pool size, bather load and other factors. Typically residential pools are drained every 3-5 years. Commercial or public pools may be drained annually.
When draining a pool:
– Backwash and clean filters before draining to remove contaminants.
– Drain slowly, no more than 2-3 inches per hour to prevent structural damage. Mark the water level.
– Direct water away from the house foundation or nearby structures. Prevent erosion and flooding.
– Clear debris from the empty pool. Pressure wash and scrub surfaces. Make repairs.
– Follow local regulations for drainage water disposal. Do not drain straight into the storm sewer system.
– Refill slowly and shock the new water to burn off any organic matter.
– Balance chemicals and get recirculating equipment operating again before swimming.
Draining a pool properly takes patience but helps prevent long-term water quality issues and extends the pool’s overall life.
Conclusion
Determining the water volume for a round swimming pool requires measuring the diameter, calculating radius, multiplying by depth, converting units to gallons, and allowing for real-world factors. A 24′ diameter by 4′ deep pool will hold around 13,000 gallons. This large volume results in tremendous weight that must be properly structurally supported. Filling a residential pool may take 24-48 hours and cost $50-$100 based on local water rates. To maintain water quality and long-term durability, pools should be periodically drained and refilled every few years under controlled conditions. Following proper fill and drain procedures will ensure safe, clear, and healthy pool water for swimmers to enjoy.
